Mystical Dispute

This is a Blue counterspell in the world of Teferi, Time Raveler – which is the most obvious target as well, since we no longer have access to Spell Pierce after Standard rotation. The best thing about this card is that it is flexible enough on its own (though pretty mediocre in a worst case scenario) unlike Spell Pierce which can only target noncreature spells.

If we want to go one step further, counterspell wars are set to be more interesting as we also have Dovin’s Veto, Veil of Summer and a whole bunch of other ones that would make this an interesting sideboard card. It seems likely that this could be a cycle of cards for each color as well.